Successful ultra-thin oxide measurement quality control and quantification of measurement error on ellipsometry

The control factors in controlling ultra-thin oxide measurement error on ellipsometry have been identified. In this work, we investigated some aspects of precision and accuracy, as applied to ellipsometry. A typical method was applied to take a routine measurement on a stable thickness sample using the measuring instrument. In the investigations, two main themes are well discussed respectively: the robustness of ellipsometer monitoring strategy in ultra-thin oxide, and the analysis of mechanical errors on the ellipsometer. The errors investigated include the preparation of master standard wafers, wafers conditioning and tool monitoring method. The mechanical errors are analyzed for the temperature of the optical chamber, optics and navigation accuracy.